1. Field of the Invention
The present invention relates to a cryopump and a vacuum pumping method.
2. Description of the Related Art
A cryopump is a vacuum pump for pumping gas molecules by trapping them by condensation or adsorption onto a cryopanel cooled to a cryogenic temperature. The cryopump is generally used to achieve clean vacuum environment that is required for a semiconductor circuit manufacturing process and the like. In an application of the cryopump, which is, for example, ion implantation process, the most of the gas to be pumped is a non-condensable gas such as hydrogen. The non-condensable gas can be pumped only by adsorption onto an adsorption region that is cooled to a cryogenic temperature.